【作者】 张建强；

【导师】 王作成；

【作者基本信息】 山东大学 ， 材料加工工程， 2013， 硕士

【摘要】 DC03钢是一种典型的低碳铝镇静钢,在炼钢阶段使用过剩的铝做脱氧剂,脱氧完全,钢质纯净。DC03钢板具有屈服强度、抗拉强度较低,塑性、冲压性能较好等特点,是第二代深冲钢板的代表。目前,DC03钢板广泛用于汽车零部件以及电器产品零部件等延展性要求比较高的产品。DC03钢板的生产工艺主要是炼钢、热轧、酸洗、冷轧、退火和平整。室温下,钢的组织是铁素体和游离渗碳体,铁素体的晶粒度以及游离渗碳体评级都对DC03钢的性能有很大影响。专家普遍认为,冷轧和退火工艺对DC03钢板室温组织有很大影响作用,是该钢种生产中最为重要的一环。目前对于DC03钢板的研究,多是针对冷连轧工艺条件,而对于可逆轧制的研究则相对较少。为系统研究可逆冷轧条件下冷轧和退火工艺对于DC03钢板组织和性能的影响,为企业生产提供理论指导,本课题采用HC单机架可逆轧机,对DC03冷轧原料板进行轧制,并在不同轧制压下率条件下取样,分别进行退火实验,最后检测各试样的组织和性能。实验发现,DC03冷轧钢板在480℃左右开始发生再结晶,680℃时再结晶完成,晶粒均匀,约为8级,此时性能稳定。冷轧压下率对再结晶组织和性能有重要作用,当压下率为70%左右时,试样退火后综合性能(强度、硬度、塑性、深冲性能)最好。另外,分级退火实验表明,在550℃保温2小时,然后再加热到700℃保温4小时,采用这种加热制度,有利于获得饼形晶粒,对于提高钢板的深冲性能有很大积极意义。更多还原

【Abstract】 DC03steel is a type of low carbon Al-killed steel, which is deoxidized completely due to the use of excessive deoxidizer. DC03steel sheet, the typical second generation of deep drawing steel, has quite low yield strength and tensile strength and good plasticity and stamping property. DC03steel sheets are being widely used in the products requiring high ductility such as automotive and electrical appliance parts.The production process of DC03steel includes smelting, hot rolling, pickling, cold rolling, annealing and smoothing. The microstructure of DC03steel at room temperature mainly consists of ferrite and free cementite. Experts and researchers are in agreement with that the cold rolling and annealing process have a great influence in the grain size of ferrite and the grade of free cementite. At present, the researches and achievements are concentrated in the continuous cold rolling process, while the studies on reversible cold rolling are rarely reported.In order to investigate the effect of the parameters of the cold rolling process and annealing process on DC03steel sheets, the samples in this paper were cold rolled in HC Single-stand reversing cold mill to different reduction ratio, then reheated to different temperature to recrystallize, and last tested the microstructure and properties of each sample.The study indicates that the cold rolling samples start to recrystallize around480centigrade and finish the recrystallization when the temperature rise to680centigrade. The size of grain is about the grade of8and the performance conforms to the requirements of DC03steel. The cold rolling ratio is an important parameter. The samples of70percent reduction ratio show the better performance in the plasticity and stamping property than ones of other reduction ratios. In addition, the experiment shows that the grain shape is flat when the samples are held for2hours at550centigrade before raised to700centigrade, which is beneficial to improve deep drawing properties of steel sheets.更多还原